We've had two companies so far which want to use DITA 1.3 because of the
default MathML support but they also want to use entity references in
the MathML content.
The MathML DTDs have a rich set of entity definitions but the decision
seems to have been to remove the possibility of using those entities
when MathML is embedded in DITA content.
Could this be reconsidered? The specification does not seem to state
that the MathML which can be embedded by default in DITA cannot use
entity references.
So maybe the MathML DTDs bundled with the DITA 1.3 standard could be
just edited to remove this limitation.
The "mathml3-ditadriver.dtd" explicitly ignores these entities by
redefining a certain parameter entity: